PURPOSE: To evaluate the efficacy and toxicity of gemcitabine and cisplatin combination chemotherapy, we conducted a phase II study of this regimen in patients with advanced non-small cell lung carcinoma (NSCLC). MATERIALS AND METHODS: From June 2001 to August 2003, 36 chemotherapy- naive patients with stage IIIB or IV NSCLC were enrolled. The median age was 59 years (range, 42 to 75 years), and performance status was 0 or 1. Eleven patients had stage IIIB disease, and 25 patients had stage IV disease. 1, 000 mg/m2 of gemcitabine was administered on day 1 & 8, and 60 mg/m2 of cisplatin was administered on day 1. Each cycle was repeated every 21 days. RESULTS: Everyone subject who participated were assessable. A total of 160 cycles of chemotherapy were delivered, and the median number of chemotherapy courses was 3.5 (range, 2 to 9). Two patients (5.6%) achieved a complete response, and 14 patients (38.9%) achieved a partial response. The overall response rate was 44.5% (95% confidence interval [CI], 32.5 to 56.5%). The median follow-up duration was 9.3 months. The median time to disease progression was 8.6 months (95% CI 7.4 to 9.9 months), and median survival time was 12.2 months (95% CI, 10.5 to 12.9 months). Grade 3/4 neutropenia occurred in 9 patients (25.0%), neutropenic fever occurred in 3 patients (8.3%), and grade 3/4 thrombocytopenia occurred in 7 patients (19.5%). Mild forms of non-hematologic toxicities, such as nausea, vomiting or skin reactions, were observed. CONCLUSION: The combination of gemcitabine and cisplatin in a 21-day schedule is an effective regimen for patients with NSCLC in its advanced stages.